Most lung cancers are caused by cigarette smoking. The more cigarettes you smoke per day and the earlier you started smoking, the greater the risk of lung cancer.

Second-hand smoke has also been shown to increase risk. Government surveys show that as many as 3,000 people each year develop lung cancer from second-hand smoke. High levels of pollution, radiation, and asbestos exposure may also increase risk.

Lung cancer begins by changes in cells that line the airways and can invade adjacent tissues before symptoms are noticed.

There are many types of lung cancer, but most can be categorized into two basic types, "small cell" and "non-small cell." Small cell lung cancer is generally faster growing than non-small cell, but more likely to respond to chemotherapy.

• Small cell cancer is divided into "limited stage" (generally cancer confined to the chest) and "extensive stage" (cancer that has spread outside the chest).
• Non-small cell cancer is divided into four stages, I-IV. Most patients with stage I and II non-small cell tumors and some patients with stage III tumors can undergo surgery with the goal of cure. Stage IV denotes cancer that has spread to other sites in the body (most often bone, brain, or liver) and is, in most cases, not curable.

Men and women die from lung cancer more than any other type of cancer. Lung cancer occurs most often in people between 55 and 65 years old.

• Cough
• Bloody sputum
• Shortness of breath
• Chest pain
• Loss of appetite
• Weight loss

Additional symptoms that may be associated with this disease:

• Weakness
• Swallowing difficulty
• Nail abnormalities
• Joint pain
• Hoarseness or changing voice
• Fever
• Facial swelling
• Facial paralysis
• Eyelid drooping
• Bone pain or tenderness

Listening to the chest with a stethoscope (auscultation) can sometimes detect fluid that has collected around the lungs from a cancer.

Tests that may be performed include:

• Chest X-ray
• CAT scan of the chest
• Bronchoscopy with washings and biopsy for cytology
• Pleural biopsy
• Lung needle biopsy
• Mediastinoscopy with biopsy
• Open lung biopsy
• Direct surgical resection

This disease may also alter the results of the following tests:

• PTH
• Serum sodium
• CEA

The treatment depends upon the type of cancer and the stage of the disease.

For small cell cancer, chemotherapy and radiation are usually used when the disease is confined to the chest -- so called "limited stage" disease. Chemotherapy alone is used in other situations (e.g., extensive stage disease).

For non-small cell cancer:

• Surgical resection (cutting out the tumor) is usually done when the cancer has not spread beyond the lung and selected lymph nodes -- stage I, II and selected cases of stage III.
• The combination of chemotherapy and radiation therapy is often used for cancer confined to the lung and lymph nodes that cannot be removed by surgery (stage III).
• Some patients will undergo chemotherapy or a combination of chemotherapy and radiation prior to surgery.
• Chemotherapy alone is used when the cancer is metastatic (stage IV); chemotherapy has been shown to prolong survival and improve quality of life.

• Spread of disease beyond the lung
• Side effects of surgery, chemotherapy, or radiation therapy

If you smoke, stop smoking. Try to avoid second-hand smoke.

There is no conclusive evidence that screening for lung cancer with chest X-rays or CT scans is beneficial for patients at high risk of developing lung cancer. However, some recent studies have suggested that specialized CT scans called "spiral CT scans" may help improve cure rates by detecting lung cancer at an earlier stage. This is still under investigation.